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Update 2014 Dec 23: This template used to only take 9 parameters. This limit has been removed.

This template is used inside other templates. It takes any number of parameters and returns the first found to be defined and non-empty. If none is found, nothing is returned. Typical usage is like this:

{{If empty |{{{logo|}}} |{{{image|}}} |{{{picture|}}} |default.svg}}

("Return {{{logo|}}} if it has a value; else {{{image|}}} if it has a value; else {{{picture|}}} if it has a value; else return "default.svg".")

This returns the first of the parameters logo, image and picture that is defined and non-empty, otherwise "default.svg".

Contents

Rationale

The MediaWiki parameter default function doesn't return the default value for empty parameters. That is, {{{logo|default.svg}}} does not return "default.svg" if the template was called like this: {{template|logo=}}.

("If {{{logo}}} has a value, return it; else if {{{image}}} has a value, return that; else if {{{picture}}} has a value, return that; else return "default.svg".")

In these cases, {{if empty}} produces the simpler syntax (as above):

{{if empty |{{{logo|}}} |{{{image|}}} |{{{picture|}}} |default.svg}}

Piping

Parameters used with {{if empty}} must be piped – i.e. include the vertical bar (pipe) symbol("|") as a trailing character – so that empty or undefined parameters aren't treated as text and returned incorrectly. Hence, for example, {{{logo|}}}, {{{image|}}} and {{{picture|}}} rather than {{{logo}}}, {{{image}}} and {{{picture}}} in the above examples.

Examples

Code

Result

{{if empty}}

Returns an empty string.

{{if empty|one}}

one

Returns the first parameter that is defined and not empty.

{{if empty|one|two}}

one

{{if empty|one|two|three|four}}

one

{{if empty||two}}

two

The first parameter is empty/undefined, so is passed over.

{{if empty||two|three|four}}

two

{{if empty||two||four}}

two

{{if empty||||||||||ten}}

ten

Unlike in previous versions, this template is no longer limited by 9 parameters.

{{if empty|}}

The only parameter is empty or undefined, so returns an empty string.

{{if empty||||}}

Returns an empty string.

{{if empty|{{{1|}}}|{{{2|}}}|three}}

three

{{if empty|{{{1}}}|{{{2}}}|three}}

{{{1}}}

No pipe-characters following the names of the first two parameters ("1" and "2"), so the first of these returned as text ("{{{1}}}").

{{if empty|{{{logo|}}}|two}}

two

{{if empty|{{{logo}}}|two}}

{{{logo}}}

No pipe-character following the parameter name "logo", so the text "{{{logo}}}" returned.

{{if empty|p=q}}

The template identifies the parameters it receives as parameters 1 to 9, not using names such as "p", etc.